In the nuclear power industry, nuclear reactors must be designed so as to withstand a variety of postulated accidents. Probably the most traumatic, if not most important, potential accident to be avoided is a loss of coolant accident (LOCA) involving the nuclear reactor. This occurs when there is a breach in the cooling system causing a drop in pressure along with a loss of coolant. As can be imagined, without any coolant in the reactor core, the core will overheat, potentially causing severe damage not only to the structure but also to the surrounding environment.
The principal method of mitigating such an accident is to flood the reactor with coolant. This must occur as soon as possible after the cooling system loses pressure in order to absorb the heat that builds up in the core during the LOCA. This usually involves adjacent storage tanks of emergency coolant that are coupled to the reactor piping. In some cases these tanks are under pressure and in others, pumps are provided to deliver the coolant to the reactor. This emergency coolant is injected into the reactor piping in any of several locations such as hot leg piping, cold leg piping, through the wall near the top of the reactor vessel, or by piping arrangements to the plenum area above the reactor core. However, one major drawback of tying into the reactor piping is the possibility that the break will prevent the fluid from reaching the reactor core.
It is thus an object of this invention to provide a means for delivering emergency coolant directly to the reactor core inlet without relying upon the reactor piping for delivery. Another object of this invention is to provide a means for delivery that will not interfere with or utilize the normal core cooling piping required for operation. A further object of this invention is to provide a means for delivering emergency coolant without it flashing or evaporating due to the high heat involved or the pressure difference encountered.